log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
%%%% Error Creating SessionFactory %%%%
org.hibernate.HibernateException: JDBC Driver class not found: com.mysql.jdbc.Driver
at org.hibernate.connection.DriverManagerConnectionProvider.configure(DriverManagerConnectionProvider.java:66)
at org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider(ConnectionProviderFactory.java:124)
at org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider(ConnectionProviderFactory.java:56)
at org.hibernate.cfg.SettingsFactory.createConnectionProvider(SettingsFactory.java:366)
at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:60)
at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:1881)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1174)
at com.cn.hibernate.HibernateSessionFactory.<clinit>(HibernateSessionFactory.java:31)
at com.cn.test.testhibernate.main(testhibernate.java:18)
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at org.hibernate.util.ReflectHelper.classForName(ReflectHelper.java:108)
at org.hibernate.connection.DriverManagerConnectionProvider.configure(DriverManagerConnectionProvider.java:61)
... 8 more
%%%% Error Creating SessionFactory %%%%
org.hibernate.MappingException: Could not read mappings from resource: com/cn/user.hbm.xml
at org.hibernate.cfg.Configuration.addResource(Configuration.java:485)
at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1465)
at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1433)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1414)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1390)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1310)
at com.cn.hibernate.HibernateSessionFactory.rebuildSessionFactory(HibernateSessionFactory.java:69)
at com.cn.hibernate.HibernateSessionFactory.getSession(HibernateSessionFactory.java:53)
at com.cn.test.testhibernate.main(testhibernate.java:18)
Caused by: org.hibernate.DuplicateMappingException: Duplicate class/entity mapping com.cn.user
at org.hibernate.cfg.Mappings.addClass(Mappings.java:118)
at org.hibernate.cfg.HbmBinder.bindRoot(HbmBinder.java:154)
at org.hibernate.cfg.Configuration.add(Configuration.java:386)
at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:427)
at org.hibernate.cfg.Configuration.addResource(Configuration.java:482)
... 8 more
Exception in thread "main" java.lang.NullPointerException
at com.cn.test.testhibernate.main(testhibernate.java:19)

解决方案 »

  1.   

    hibernate什么时候到8.5版本咯。算我孤陋寡闻了
      

  2.   

    错误已经给出来了,JDBC Driver class not found: com.mysql.jdbc.Driver
    找不到类com.mysql.jdbc.Driver
    把mysql-connector-java-version-bin.jar 复制到 tomcat 的 common/lib 目录另外看看数据库服务开没开。
      

  3.   

    org.hibernate.HibernateException: JDBC Driver class not found: com.mysql.jdbc.Driver
     
    没有添加数据库驱动
    org.hibernate.MappingException: Could not read mappings from resource: com/cn/user.hbm.xml
     user.hbm.xml在配置文件中注册了没有